José Mourinho fired a psychological shot across the bows of his former club, Chelsea, last night after watching his Internazionale team edge the first leg of their Champions League last-16 meeting by predicting that his presence back at Stamford Bridge in the return fixture in three weeks' time could prove decisive.

Inter won courtesy of Esteban Cambiasso's second-half blast, yet Chelsea could reflect with some pride at their performance over an absorbing 90 minutes. They boasted 18 shots to Inter's eight while they enjoyed 56% of the possession. They were also left to lament what everyone in their dug-out and dressing-room felt was a "stonewall" penalty, when Walter Samuel appeared to trip Salomon Kalou just before the interval. Even Samuel admitted that the Spanish referee, Manuel Mejuto González, ought to have pointed to the penalty spot. "I am honest, Italy won't change me," said the Argentinian. "It was a penalty. Overall, I like the referee."

The second leg is sure to be coloured by Mourinho's return to Stamford Bridge where he tasted such success and adulation during his time in charge and the Portuguese warmed to the theme as the dust settled on the tie's halfway point.

"I have to control my emotion and be professional like the Chelsea players were tonight," he said. "In the tunnel it was not a normal game for me or them but after that it was a normal game. The next time I go back to a different dressing room and dug-out and they know that normally Mourinho is lucky at Stamford Bridge."

The bookmakers have installed Chelsea as the favourites to progress into the quarter-finals as they chase the trophy that the owner Roman Abramovich craves. Neither Mourinho nor his Chelsea counterpart, Carlo Ancelotti, could call it any differently than 50-50 but, had González penalised Samuel, Chelsea might have found themselves in the ascendancy.

"I think it was a penalty in the first half," said Ancelotti, "but a penalty is when the referee blows the whistle. We can say that we were unlucky this evening and we hope it will be better in the future. González is a very good referee with a lot of experience. Inter are a little bit less predictable than they were last year but, looking at what happened tonight, I believe we have quite a lot of chances to go through."

Mourinho felt that it was "obviously not the best result" for Inter but he allowed himself a moment of satisfaction. "Of course, I'm happy inside," he said. "I was saying a few weeks ago that as a professional I want to win more than anybody else. It was a high-level game, no surprise, just my team playing with the quality they have. I told the players they are not better than us. Chelsea can player better and so can we. Now it will come down to the team with the greatest ambition.

"We showed that we can be a very big team in the Champions League. Playing the first leg at home is always going to be complicated but we believe we can do well at Stamford Bridge. We had very good chances against Manchester United last season and why can't that happen again?"